9. In standardizing roughly 0.05M H, SO, solution,1.325g of pure an hydrous sodium carbonate were made up to 250cm' and 25cm' of the solution needed 23.5 cm of
the acid. Calculate the concentration of the acid in gom*. If 906cm? of the acid
were left after the titration, how many cm' of water must be added to the
remaining acid to make it exactly 0.05M?(Ans 5.212, 57.82) SOMEONE PLEASE EXPLAIN HOW TO DO IT!!

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.